Find the movement of the field

$\displaystyle F(x,y) = (x^2-y)i + (x-y^2)j$

arrond the curve $\displaystyle \alpha$ which is the boundary of the region in 1° quedrant understood by coordinated axes and the circle $\displaystyle x^2+y^2=16$

My solution

$\displaystyle \int_0^{\frac{ \pi}{2}} (-64cos^2tsint +16sen^2t+16cos^2t-64sen^2tcost)dt = 8 \pi$

Correct ?